Means of erecting concrete floor and roof slabs in the construction of multi-floor buildings



Oct. 27, 1964 D. D. R. RANKIN ETAL 3,154,292

MEANS OF ERECTING CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS Original Filed Nov. 27, 1959 7 Sheets-Sheet 1 L 1964 D. D. R. RANKIN ETAL 3,154,292 MEANS OF ERECTING CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS Original Filed Nov. 27, 1959 7 Sheets-Sheet 2 Oct. 27, 1964 RANKIN ETAL, 3,154,292

MEANS OF ERECTING CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS Original Filed Nov. 27, 1959 7 Sheets-Sheet 3 Oct. 27, 1964 MEANS OF ERECTI'NG D R. RANKIN ETAL CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS 7 Sheets-Sheet 4 Original Filed Nov. 2'7, 1959 Oct. 27, 1964 D. D. R. RANKIN ETAL 3,154,292

MEANS OF ERECTING CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-F'LOOR BUILDINGS Original Filed Nov. 27, 1959 7 Sheets-Sheet 5 Oct. 27, 1964 D. D. R. RANKIN ETAL 3,154,292

MEANS OF ERECTING CONCRETE FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS Original Filed Nov. 27, 1959 7 Sheets-Sheet 6.

2 7 9 2 m 4 h 5 4 1-" S 3 w e h s 7 1964 D. D. R. RANKIN ETAL MEANS OF ERECTING CONCRETE FLQOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS Original Filed Nov. 27, 1959 Ha/Z.

United States Patent Office 3,154,292 Patented Get. 27, 1964 3 154,292 MEANS OF ERECTENQ; NCRETE FLGGR AND RG SLABS m THE C GNSTRUQTKQN G1 MULTI-FLOOR BUTLDTNGS Dudley David Raye Rankin, 250 Railway Parade, Kogarah, near Sydney, New South Wales, Aushalia, and Kelvin Edgar Anderson, 16 Eden St, Arnclifie, near Sydney, New onth Wales, Australia Griginfi application Nov. 27, 1959, Ser. No. 855,554. Divided and this application Jan. 21, 1963, Ser. No. 253,782 Claims priority, application Australia, Nov. 26, 1958, 43,692/58, Patent 2%,136 8 Claims. (Cl. 2S4105) This application is a division of our former application, Serial No. 855,564 filed November 27, 1959 now abancloned.

This invention relates to that form of construction of multi-fioor buildings where concrete floor and roof slabs are made on the site between or about building columns at ground level or at a convenient working level and are subsequently elevated to designed positions and there fixed to the building columns.

One object of the present invention is to reduce the risk of buckling of the building columns during the lifting of the slabs. This risk was encountered hitherto by reason of the fact that the lifting means were located on the top of the columns and the columns could not be effectively braced intermediate the top and bottom.

Another object of the invention is to provide means whereby the lifting of the slabs can be accomplished on partly erected columns without interfering with the progressive erection of the columns.

A further object of the invention is to provide means whereby one or more slabs can be elevated and secured at temporary locations, thus permitting further slabs to be made on the working level site in a continuously progressive building program.

A still further object of the invention is to provide lifting means adapted to be secured to the sides of all the columns which support the lift at a convenient working height for a progressive lift, the lifting means consisting of a number of independent units which can be operated independently or interconnected and operated together simultaneously and stopped automatically or manually.

One advantage resulting from the invention is that the mounting of the lifting means on a column or the connecting of lifting means to a column can be effected by operators working on a slab. There is no need for operators to climb to excessive heights on the columns.

A slab or a number of slabs superimposed one upon the other, are made on the ground or at a convenient working height, perpendicularly below the position the slabs are to occupy in the finished structure. The slabs have sleeves embedded therein at the position of each column. The columns to support the slabs are erected to a convenient working height comeasurable with lateral stability before or after the formation of the slab or slabs and the sleeves in the slab or slabs are slidable on the columns. Elevating means are anchored to the sides of the columns above or below the slab or slabs to be lifted at such distance from the slab or slabs as will permit the lifting of the slab or slabs the distance required, which distance may be a portion of the distance of the ultimate lift. The elevating means are connected to the slab or slabs and actuated to achieve a lift. Alternatively, the elevating means are anchored to a slab (which may have other slabs above and resting upon the connected slab) and connected to the sides of the columns, at such distance above the uppermost slab as will permit lifting as aforesaid.

The slab or slabs can be temporarily secured to the columns at positions intermediate the final positions and elevating means re-located to achieve a further lift. The process is repeated until the slabs are elevated to their final position when they are finally secured to the colurnns. For the lifting of some of the slabs, such as the final lift of the roof slab, the elevating means may be located below the slab. In this case, the elevating means are connected to the sides of the columns and a slab carrier is mounted on the elevating means.

During the process of erecting high buildings, some of the slabs are left temporarily secured to the columns at selected temporary elevated positions to provide lateral stability in the columns, firstly while the column structure is being extended and secondly while other slabs are being progressively elevated to their designed position.

Extensions of the columns can be erected progressively by working from the top-most slab secured at a temporary position. In efiect, the topmost slab becomes a working platform.

According to the invention preferably two cases have means whereby they can be anchored to the sides of a column. That is to say two cases are anchored to each column used in the lifting of slabs. Each case has a screw located in and projecting perpendicularly through it. The screw has means whereby it is connected to a sleeve in a slab or to the sleeve in the lowermost of a number of slabs. Alternatively the cases are anchored to a slab as aforesaid and the screws are connected to the columns. There are two abutment members in the case in spaced relationship through which the screw passes. One abutment member is fixed in the case and the other is movable vertically therein. Springs are incorporated to move the movable abutrnent member away from the fixed abutment member. Two nut blocks, called herein the first and second nut blocks, are mounted on the screw. The first nut block is adapted to register with the fixed abutment member and the second nut block is adapted to register with the movable abutment member. The movable abutment member has two slide faces remote from the second nut block located one on each side of the screw in parallel spaced relationship. Two slide members in the case are located in juxtaposition to the slide faces. Two wedge blocks are mounted between the slide members and the slide faces. Means are incorporated to reciprocate the wedge blocks and other means co-active with the wedge actuating means are arranged to rotate the first nut block to engage the fixed abutment member when the wedges move the screw as a result of the second nut block being in engagement with the movable abutment member and to rotate the second nut block to reengage the movable abutment member when the wedges are retracted and the movable abutment member is moved by the springs as permitted by the retraction of the wedges.

The invention is described in greater detail with reference to the annexed drawings wherein:

FIGURE 1 is a perspective view of a pair of lifting units anchored to the sides of a column and connected to a slab.

FIGURE 2 is a fragmentary perspective view of the two lifting units with the covers removed from one revealing part of the lifting mechanism.

FIGURE 3 is an end elevation partly in section showing another part of the lifting mecham'sm.

FIGURE 4 is a sectional elevation on plan 44 of FIGURE 1.

FIGURE 5 is a sectional elevation on line 55 of FIG- URE 4.

FIGURE 6 is a sectional plan on line 66 of FIG- URE 4.

FIGURE 7 is a sectional elevation on line 77 of FIG- URE 6.

FIGURE 8 is a plan of one of the nut blocks.

FIGURES 9 and 10 are sectional plans on lines 9-9 and 113-111 respectively of FIGURE 4 showing the means for operating the nut blocks.

FIGURE 11 is a diagrammatic view of the power mechanism mounted on a trolley.

FIGURE 12 is a diagrammatic view showing a lifting 'unit anchored to a slab and connected to a column.

FIGURE 13 is also a diagrammatic view showing how an elevating unit can be located below a slab to achieve a lift.

( FIGURE 14 is a diagrammatic lay-out of one of a pair of trip levers and pawls used to lower a slab.

The columns preferred in the construction of buildings according to the present invention are of substantially square section consisting of inset webs 1 joined by side members 2. Pads 3 are welded to the webs 1 to provide supports for the elevating mechanism anchor chocks and also supports for slab anchor chocks. It is preferred to use twin elevating units for, and as illustrated, attached to each column but in some positions one elevating unit only may be attached to a column.

Each elevating unit consists of a case 4 having on one end, here shown as the top, a tubular member 5 with a collar 6 on the top thereof. The case is anchored to a column by clamp plates 7 which are secured by bolts 8. Chocks 9 rest on the pads 3 and the bottom edges of the clamp plates 7 rest on and are supported by the chocks 9. A carrier plate 11) fixed to each clamp plate 7 and supported by gussets 11, has a hole through which the tubular member 5 passes, and the collar 6 rests on the carrier plate 16.

A screw 12 projects through the case 4 and through the tubular member 5. On the bottom of the screw 12 when positioned as illustrated to lift a slab, there is a head 13 which is adapted to pass through a key-hole slot 14 in a flange 15 forming part of a sleeve 15 embedded in a slab indicated at 17. The arrangement is such that the head 13 interlocks in the keyhole slot and cannot be released so long as the case is anchored to a column. The head may pass through two or more slabs superimposed one on another and be interlocked in the lowermost slab so that several slabs are elevated together.

In the case 4 there are two abutment members 18 and 19 through which the screw 12 passes. The abutment member 18 is fixed in the case 4 while the abutment member 19 is slidable vertically therein. The abutment member 19 is thrust away from the abutment member 18 by springs 20.

Two split nut blocks 21 and 22 (called herein the first and second nut blocks respectively) are mounted on the screw 12. The construction of each nut block is such that the two parts can be locked together on the screw and they can be separated and removed from the screw and from the case, thus permitting removal and replacement of a screw without disturbing the other mechanism in the case. The two parts of each nut block are hinged together at one side (see FIGURE 8) by a hinge pin 81. Opposite the hinge pin one part of each nut block has a catch 82 and the other part has a latch bar 83 mounted thereon. The latch bar is moved to engage the catch 82 by a spring 84.

The first nut block 21 is adapted to register with the fixed abutment member 18 and the second nut block 22 is adapted to register with the movable abutment member 19.

The movable abutment member 19 has two slide faces remote from the second nut block 22 one on each side of the screw 12 in parallel spaced relationship. Two sets of rollers 23 (see FIGURE 4) held in cages 24 have a limited rolling movement on the slide faces. Two slide members positioned to form ramps are mounted in the case and they support two sets of rollers 25 in cages 26 in juxtaposition to the rollers 23. These rollers 25 have the same rolling movement as the rollers 23. Two wedge blocks 27 and '28 are mounted between the rollers 23 and 25 respectively. Stop plates 2) on the small ends of the wedge blocks and stop plates 30 on the slide faces and slide members respectively confine the movement of the sets of rollers 23-25. At the large end each wedge block 27-28 is connected to a cross head 31 and the latter is connected to a plunger rod 34 in double acting hydraulic cylinder 35 pivotally mounted as at 36 in the case 4.

As shown in the drawings there is a plate 37 fixed in the case 4- above the first nut block 21 and a similar plate 38 fixed in the case 4 above the second nut block 22. For simplicity of description these parts and associated parts are described in this order notwithstanding that the case may be inverted for certain lifting operations. The plates 37-38 each has an annular disc 39-411 rotatably mounted therein. The screw 12 passes through the discs. Each disc has thereon a pair of diametrically oppositely disposed fingers 41-42 respectively which project downwardly and engage in slots 32 and 33 in flanges forming part of the nut blocks 21-22. On top each disc has a tubular member with a sprocket 43-44 fixed thereto. The top sprocket 43 engages a chain .5 which is mounted on an idler sprocket 46 supported by a journal pin 47 fixed to the top of the case 4 and driving sprocket 48 rotatably mounted on drive shaft 49 mounted in the case The bottom sprocket 44 is engaged by a chain 50 which passes around it and driving sprocket 51 rotatably mounted on the drive shaft 49.

The drive shaft 49 has a sleeve 52 fixed thereon and this sleeve has flanges 53-54 on the respective ends thereof. The driving sprocket 48 has a carrier pin 55 which is adapted to engage a catch pawl 56 on the flange 53, and driving sprocket 51 has a carrier pin 57 adapted to engage a catch pawl 53 on the flange 54. The arrangement of these pawls 56-58 will be described later.

The drive shaft 49 also has a twin sprocket 59 with a driving chain 61 thereon supported by an idler twin sprocket 62 mounted on a journal 63 fixed to the case 4. A slide bar 64 fixed to the case 4 and to a bracket 65 also fixed to case 4 has a crosshead 66 slidable thereon and this cross head has a tooth 67 which is spring held in engagement with one of the links of the chain 641 (see FIGURES 2, 4 and 7). The tooth and chain functions as a rack and pinion. The tooth will disengage from the chain if sub jected to an overload.

A pair of rods 68 connect the crosshead 66 to the crosshead 31 so that the drive shaft 49 is rotated alternatively in opposite directions according to the movement of the plunger rod 34.

At the start of a lifting operation the wedge blocks 27-28 are in the retracted position and the second nut block 22 is in engagement with the abutment member 19. When the wedge blocks 27-28 are moved to lift a slab through the abutment member 19 any load on the nut block 21 is removed. The drive shaft 49 is rotated in one direction and pawl 56 engages the carrier pin 55 on the driving sprocket 48 which through the chain 45 screws the first nut block 21 to maintain its engagement with the abutment member 18 during the lifting stroke of the wedge blocks 27-28. Lost motion is provided between the pawl 56 and the carrier pin 55 to allow the abutment member 19 to fully take the load from the nut block 21 before the nut block 21 commences to rotate. During this movement, flange 54 is moving pawl 58 to a position ready to become operative when the Wedge blocks 27-28 begin to retract. On the retracting movement of the wedge blocks 27-28, the drive shaft 49 is rotated in the opposite direction and the pawl 53 engages the carrier pin 57 on the driving sprocket 51 which through the chain 59 screws the second nut block 22 to follow the movement of the abutment member 19 effect ed by the springs 20 so that when the wedge blocks 27- 215 are fully retracted, the abutment member 19 is in engagement with the second nut block 22 to take a new lift. Lost motion is provided between the pawl 58 and the carrier pin 57 to allow the abutment member 18 to fully take the load from the nut block 22 before the nut block 22 commences to rotate. During this movement of the second nut block, flange 53 is moving pawl 55 to a position ready to become operative when thewedge blocks 27-28 begin the next lifting stroke. In effect, although the drive shaft 49 is rotated alternately in two directions, the nut blocks 21-22 are screwed in one direction.

The pawls 56 and 58 are of the same construction and each incorporates a reversing pawl 71 and 72 respectively. The construction is shown diagrammatically in FIGURES 9 and 10. The pawls 56-58 are pivotally mounted as at 69 on the flanges 53-54- (see FIGURE 4) and they each have a tongue 7% to register with the carrier pins 55-57. The reversing pawl component 71-72 is associated with each of the pawls 56-53. These pawl components are pivotally mounted as at 73 on the flanges 53-54 and they each have a tongue '74 to register with the carrier pins 55-57. The tongue 7% is adapted to interlock with the tongue 74 in the position shown for the pawls 55-53 to operate as described above. In order to cause the mechanism to operate in the reverse direction the pawls are moved so that the tongues 79-74 interlock in the reverse position to that shown in FIGURES 9 and so that the tongue 74 will engage the pins 55-57 respectively. The pawls are held in either operative position by spring 75.

At the start of a reversin movement, the wedge blocks 27-23 are in the retracted position and the second nut block 22 is in engagement with the abutment member 19 but the weight is being held by nut block 21 in engagement with abutment member 18. No lost motion is provided between reversing pawl 72 and carrier pin 57 therefore the nut block 22 is rotated immediately the wedge blocks 27-28 move. In this movement the nut block 22 rotates moving in the direction of abutment member 18 and is closely followed by abutment member 19 through the action of the wedge blocks 27-28.

At a point when abutment member 1 has nearly reached the limit of its travel pawl retracting pin 89 engages trip lever 95) (see FIGURE 2) which trips pawl 72 and disengages its tongue 74- from carrier pin 57. This action steps the rotation of nut block 22 and abutment member 19 engages nut block 22 causing the load to transfer to it from nut block 21.

During this part of the reversing movement, the reversing pawl 71 (FIGURE 14), has been free-wheeling in an anticlockwise direction. Just prior to reaching the posi tion shown in FIGURE 14, the pawl retracting pin $1 engages the rainp face 5 3 of the trip lever 92, causing the trip lever 92 to pivot about its pin 94 away from the stop 95 against the resistance of a spring 96, to keep the working face 97 of the trip lever 92 inoperative during the follcwirn sequence.

No lost motion is provided between reversing pawl 71 and carrier pin 55 therefore the nut block 21 is rotated immediately the wedge blocks 27-26 start to retract. The nut block 21 rotates in a direction which keeps it out of en agement with abutment member 13 while the retracting action of the wedge blocks 27-28 lowers the load. At a point 'when the wedge blocks 27-28 have nearly reached the limit of their retraction, pawl retracting pin 91 engages working face of trip lever 92 which is of the same construction as trip lever 99 and which trips pawl 71 and disengages its tongue 74 from carrier pin 55. This action stops the rotation of nut block 21. Nut block 21 engages abutment member 18 as the retracting stroke of wedge blocks 27-23 terminates, causing the load to transfer to it from nut block 22.

During this part of the reversing movement, reversing pawl 72 is acted upon and free-wheels in the manner described for reversing pawl 71.

The reverse movement of the mechanism is required to lower a slab onto checks 9 which are supported by the pads 3.

In the description of the invention, with reference to FIGURES l to 11, the cases 4 are anchored to the column and the screws are connected to a slab 17. The same result can be achieved by anchoring the cases 4 to a slab 17 and connecting the screws 12 to the columns as shown in FIGURE 12. In many operations, this method of mounting the elevating means is preferred because it avoids lifting of the case i above a convenient working height. In this arrangement, some cases are inverted with the tubular members 5 located at the bottom.

In FIGURES 1 to 12, the elevating means are located above the slabs which are to be raised. FIGURE 13 shows how the elevating means can be mounted on columns as in FIGURES l to 11, but below a slab or slabs. This method (FIGURE 13) is desirable for elevating a roof slab to its final position. The advantage of this arrangement is that temporary extensions of the columns are not requ red and the load carrying screws are in tension as in all the other arrangements.

In order to eifcct a lift as in FIGURE 13 a base plate 86 is mounted on top of each case 4 and a slab carrier 87 (which may be tubular) is mounted on the base plate and supports the slab.

The actuating mechanism consists of a complete unit for the elevating means on each column. Each unit comprises a trolley 76 adapted to be movably located on a slab.

Each trolley has thereon a motor 77 connected to a hydraulic pumping unit 73. Hydraulic fluid passes from the pump to a solenoid actuated control valve, indicated at 79, and flexible pipes 88 connect the control valve to the respective ends of each pair of double acting hydraulic cylinders 35. A relief valve 99 and gauge 9% are incorporated in the hydraulic circuit. The solenoid is actuated by a switch which, in turn, is actuated by the crosshead at the respective ends of its travel. Each unit has a manual control valve thereon and the several units required to lift a slab are interconnected and synchronised by being connected in series, whereby all of the lifting units may be controlled from any one of the lifting units and during automatic operation of all units in synchronisation, every unit must complete its lifting cycle before any of the units can start another cycle, and the lifting cycles will be continued automatically as long as the operator desires. Space is provided on the trolley on each side of the pumping unit so that the two cases 4 may be transported or stored thereon without the necessity of disconnecting hydraulic or electric lines.

In operation, the vertical distance travelled during each lifting cycle is short, so that if, during a lifting operation, the elevating units on one column fail to operate and the remainder operate, no undue strain is placed on the slab or slabs being lifted. Also, during an automatic and continuous, synchronised lifting operation, it one elevating unit fails, the remainder will complete one lifting cycle only and will then stop until the fault is corrected. All elevating units may be operated individually or may be synchronised to operate in unison.

We claim:

1. Means for erecting floor and roof slabs in the construction of multi-floor buildings wherein the slabs are formed with sleeves therein which are in sliding engagement with related columns; said means consisting of a plurality of cases, each case having means for anchoring the same to the side of a related column and means for connecting said case to a slab, said connecting means including a screw located in and projecting perpendicularly through said case, said screw having means for connecting it to a sleeve in said slab, two abutment members in said case in spaced relationship through which said screw passes one said abutment member being fixed in said case and the other movable vertically therein;

springs to move said movable abutment member away from said fixed abutment member, first and second nut blocks on said screw, said first nut block being adapted to register with said fixed abutment member, said second nut block being adapted to register with said movable abutment member, said movable abutment memher having two slide faces remote from said second nut block one on each side of said screw in parallel spaced relationship, two slide members in said case juxtaposed said slide faces, two wedge blocks mounted between said slide members and said slide faces, means to reciprocate said wedge blocks, means co-active with the wedge actuating means to rotate said first nut block to engage said fixed abutment member when said wedges raise said screw as a result of said second nut block engaging said movable abutment member and to rotate said second nut block to re-engage the movable abutment member when said wedges are retracted and said movable abutment member is moved by said springs as permitted by the retraction of the wedges.

2. Means for erecting floor and roof slabs in the construction of multi-floor buildings accordingto claim 1 wherein the means for anchoring said case to case to a column consists of pads welded to a column, clamp plates secured to the column, chocks on said pads for supporting said clamp plates, a carrier plate fixed to each clamp plate, and gussets supporting said carrier plates.

3. Means for erecting floor and roof slabs in the construction of multi-fioor buildings according to claim 1 wherein the first and second nut blocks are split and the two parts hinged together at one side and have a catch and a spring actuated latch at the other side.

4. Means for erecting floor and roof slabs in the construction of multi-floor buildings according to claim 1 wherein rollers in cages are located between the wedge blocks and the slide faces and slide members respectively, said wedge blocks having stop plates on the small ends thereof, said slide faces and slide members having stop plates on the ends remote from the wedge stop plates, said rollers being free to move within the limits permitted by said stop plates, said slide members being positioned to constitute ramps.

5. Means for erecting floor and roof slabs in the construction of multi-floor buildings according to claim 1 wherein the means to reciprocate the wedge blocks con sists of a double acting hydraulic cylinder pivotally mounted in the case and having its plunger rod connected 8 to a cross-head mounted on a pair of wedge blocks, and pump means to .actuate said plunger.

6. Means for erecting floor and roof slabs in the construction of multi-fioor buildings according to claim 1 wherein the means to rotate the first and second nut blocks consist of annular discs rotatably mounted in plates fixed in the case, each disc having a pair of diametrically oppositely disposed fingers in engagement with the respective nut blocks, each disc also having a sprocket fixed thereto, chains connecting said sprockets to driving sprockets rotatably mounted on a drive shaft, means to engage said driving sprockets with said drive shaft, said drive shaft having means whereby it is 1'0- tated alternately in opposite directions by the wedge actuating means, said chain in driving engagement with the first nut block being passed around an idler sprocket so that on the lifting movement of the wedges and the engagement of its driving sprocket with the drive shaft the first nut block will be rotated to engage the fixed abutment member, said chain in driving engagement with the second nut block being arranged so that on retracting movement of the wedges and the engagement of its driving sprocket with the drive shaft the second nut block will be rotated to re-engage the movable abutment member.

7. Means for erecting floor and roof slabs in the construction of multi-floor buildings according to claim 6 wherein the means to rotate the drive shaft consists of a chain and sprocket, a cross head slidably mounted on a slide bar, said orosshead having a pawl, said pawl being spring held in engagement with said chain and having a driving connection to the wedge blocks reciprocating means.

8. Means for erecting floor and roof :sla'bs in the construction of multi-floor buildings according to claim 6, wherein the means to engage the driving sprockets with the drive shaft consist of pawls pivotally mounted on flanges fixed on the drive shaft, said pawls being adapted to engage carrier pins fixed on the driving sprockets, said pawls each having a reverse drive component and means to move the pawls or the reverse drive components into and out of actuating positions.

References Cited in the file of this patent UNITED STATES PATENTS 216,326 Hyde June 10, 1879 2,673,067 Fredrickson Mar. 23, 1954 2,758,467 Brown et al. Aug. 14, 1956 

1. MEANS FOR ERECTING FLOOR AND ROOF SLABS IN THE CONSTRUCTION OF MULTI-FLOOR BUILDINGS WHEREIN THE SLABS ARE FORMED WITH SLEEVES THEREIN WHICH ARE IN SLIDING ENGAGEMENT WITH RELATED COLUMNS; SAID MEANS CONSISTING OF A PLURALITY OF CASES, EACH CASE HAVING MEANS FOR ANCHORING THE SAME TO THE SIDE OF A RELATED COLUMN AND MEANS FOR CONNECTING SAID CASE TO A SLAB, SAID CONNECTING MEANS INCLUDING A SCREW LOCATED IN AND PROJECTING PERPENDICULARLY THROUGH SAID CASE, SAID SCREW HAVING MEANS FOR CONNECTING IT TO A SLEEVE IN SAID SLAB, TWO ABUTMENT MEMBERS IN SAID CASE IN SPACED RELATIONSHIP THROUGH WHICH SAID SCREW PASSES ONE SAID ABUTMENT MEMBER BEING FIXED IN SAID CASE AND THE OTHER MOVABLE VERTICALLY THEREIN; SPRINGS TO MOVE SAID MOVABLE ABUTMENT MEMBER AWAY FROM SAID FIXED ABUTMENT MEMBER, FIRST AND SECOND NUT BLOCKS ON SAID SCREW, SAID FIRST NUT BLOCK BEING ADAPTED TO REGISTER WITH SAID FIXED ABUTMENT MEMBER, SAID SECOND NUT BLOCK BEING ADAPTED TO REGISTER WITH SAID MOVABLE ABUTMENT MEMBER, SAID MOVABLE ABUTMENT MEMBER HAVING TWO SLIDE FACES REMOTE FROM SAID SECOND NUT BLOCK ONE ON EACH SIDE OF SAID SCREW IN PARALLEL SPACED RELATIONSHIP, TWO SLIDE MEMBERS IN SAID CASE JUXTAPOSED SAID SLIDE FACES, TWO WEDGE BLOCKS MOUNTED BETWEEN SAID SLIDE MEMBERS AND SAID SLIDE FACES, MEANS TO RECIPROCATE SAID WEDGE BLOCKS, MEANS CO-ACTIVE WITH THE WEDGE ACTUATING MEANS TO ROTATE SAID FIRST NUT BLOCK TO ENGAGE SAID FIXED ABUTMENT MEMBER WHEN SAID WEDGES RAISE SAID SCREW AS A RESULT OF SAID SECOND NUT BLOCK ENGAGING SAID MOVABLE ABUTMENT MEMBER AND TO ROTATE SAID SECOND NUT BLOCK TO RE-ENGAGE THE MOVABLE ABUTMENT MEMBER WHEN SAID WEDGES ARE RETRACTED AND SAID MOVABLE ABUTMENT MEMBER IS MOVED BY SAID SPRINGS AS PERMITTED BY THE RETRACTION OF THE WEDGES. 